The bearing isolator is a non-contacting labyrinth seal and was originally invented in 1970s. It is a mechanical device that is used to ensure that a bearing is isolated from its environment that allows the bearing to be properly lubricated. Here the bearing isolator provides a permanent bearing protection and eliminates the need for continual maintenance. Since bearing isolators ensure that there is no contact between the unitized rotor and stator there is no consumption of energy. It also means that these isolators never wear out and have long life spans. Another variant has O-rings being used for creating seals. Bearing isolators are usually made out of bronze or other metals. They also have a vapor blocking system that prevents the free transfer of vapor contamination when the equipment is cycled on or off.
Using non-contacting labyrinth seal bearing isolators in industrial equipment is an ideal way to save energy. Bearing isolators are crucial for industrial rotating equipment. It is estimated that the US can save billions of dollars in electrical power costs by shifting from contact lip seals to non-contact seals in industrial rotating equipment. The savings incurred would amount to as much as 5500 MW of energy every year.
The most common application of lip seals includes pumps, gearboxes, fans, paper machine rolls, and other types of rotating equipment. Each lip seal consumes around 147 watts of power and is plagued with a 100% failure rate. Lip seals have a life span of 2.7 months – which amounts for 2000 hours of operation. Failure to replace lip seals will lead bearings becoming contaminated or run out of oil.
Using bearing isolators in motors help in prolonging the life of the motor. A bearing protected motor can last up to twice as long as a normal motor. This is because bearing deterioration is the leading reason for motor failure. The savings incurred by the US if 38 million contacting lip seals were replaced by bearing isolators would amount to as much as, energy generated by 10 fossil fueled power plants. Using bearing isolators would also mean a reduction in tons of carbon monoxide that would otherwise be produced during the manufacturing process and a saving of $3.7 billion per year in electrical power costs.